Update shallowest_decomp_tree.hpp

Author: lrvideckis

library/trees/shallowest_decomp_tree.hpp

@@ -24,5 +24,8 @@ void shallowest(auto& adj, auto f) {
   auto cpy(adj);
   adj.assign(sz(adj), {});
   for (vi vec : order)
-    for (int v : vec) f(v), adj[v] = cpy[v];
+    for (int v : vec) {
+      f(v);
+      for (int u : cpy[v]) adj[u].push_back(v);
+    }
 }